1. Field of the Invention
This invention relates to a camera capable of changing the focal length by bringing an auxiliary lens into axial alignment with a master lens.
2. Description of the Prior Art
It is known to provide a focal length changeable camera in which when a master lens system only is in use, standard photography with a short focal length is carried out, and when the master lens system is in a forward position there is provided rearwardly thrust an auxiliary lens system, whereby telephotography may be effected. A device of this type is, for example, disclosed in U.S. Pat. No. 3,388,650, and Japanese Laid-Open Patent Applications Nos. Sho 52-76919 and Sho 54-33027.
However, such focal length changeable camera, though it is capable of performing standard photography and telephotography, cannot perform close-up photography. There has, therefore, occurred a demand to make that camera capable of performing close-up photography. Also the prior art focal length changeable camera involves the possibility of occurrence of faulty operation in that film exposure may occur during the change over between the focal lengths.
An object of the present invention is to eliminate the above-described drawbacks, and to make close-up photography possible by moving the master lens forward to a predetermined intermediate position between the standard and telephoto exposure positions, while leaving the auxiliary lens retracted from the rear optical path.
Another object of the present invention is to lock the aforesaid master lens in the predetermined position by setting a mode selector member in a close-up position.
Another object of the present invention is to prohibit a release actuation except when the master lens is in the standard or the telephoto position.
Another object of the present invention is to remove the release actuation prohibiting condition in the close-up exposure position of the master lens when the mode selector member is set in the close-up position.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.